Niggling temp gauge issue - any ideas please?

[jezza16v]

OK, its a small bumper 8v digi.
When we got this car the temp gauge was reading very high, between mid way and the hot end, but it never seemed hot and the fan came on as normal. The clocks had a buzzer & rev counter fault so we swapped them, the new temp gauge still read the same and due to a knackered fuel gauge on those clocks we changed them again for yet another set which are now fine but the temp gauge still sits at the same point. Anyway, suspecting it might be the thermostat, we changed that today for a new oem unit, still the same reading, and then we changed the black sender for a new oem unit...........still the same reading. I suppose its not really important but its very hard to ignore a gauge that's telling you the engine is too hot, on our big bumper mk 2 the rad fan would be on permanently with the gauge in that position. I can't believe all 3 gauges would be wrong, anyone got a clue as to what might be causing the temp gauge(s) to over-read?

[Lap]

What is your oil temperature reading?

[jezza16v]

Oil temp is normally 96-100, highest we've had when giving it some in the summer was 110.
I think I'll try and rig up one of the old spare temp gauges direct off the battery and sender and see what reading that gives.
I'm thinking there may be a bit of a 'short' somewhere in the wiring?

[jmsheahan]

Oil temp is normally 96-100, highest we've had when giving it some in the summer was 110.
I think I'll try and rig up one of the old spare temp gauges direct off the battery and sender and see what reading that gives.
I'm thinking there may be a bit of a 'short' somewhere in the wiring?

Thats not too bad oil temp, mines exactly the same. Out of interest do the oil temp mfa readings go up when you use something electrical i.e heaters, lights etc? Might be a bad earth somewhere.

[jezza16v]

No, everything is steady except for the high temp reading.

[Lap]

Oil temp sounds normal so you're right that the engine isn't actually running hot. Still, as you say, it's a bit off putting when the gauge tells you otherwise all the time!

Rigging up a temp gauge directly isn't a bad idea as long as it'll work like that. If it reads normal then I guess you have a wiring problem. I would then be dropping out the fuse box and checking the connections behind that while concentrating specifically on the coolant temp gauge wires (see fusebox faq)

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